PHOENIX (AP) â€” A priest was shot and killed and another was injured at a Roman Catholic church in downtown Phoenix, setting off an intense search for suspects and clues into what police called a “tragic and appalling” attack.

The surviving priest called 911 to report a burglary at the Mother of Mercy Mission near the state Capitol around 9:30 p.m. Wednesday and administered last rites to the wounded clergyman while waiting for police to arrive. The Rev. Kenneth Walker died at the hospital, and the Rev. Joseph Terra, 56, is hospitalized in critical condition with unspecified injuries.

Police have no suspects at this point. They are searching the neighborhood, interviewing the injured priest and examining physical evidence from the scene. Investigators said they are unsure how many attackers were involved and if robbery was the motive.

Police Chief Daniel Garcia called it a “tragic and appalling criminal violation.”

As police investigated the crime scene at the church, about a dozen parishioners gathered across the street, kneeling on the sidewalk and saying the Lord’s Prayer in response to the loss of their beloved clergyman. A bouquet of flowers and a photograph of the dead priest lay on the sidewalk.

Parishioner Diane sobbed as she spoke of Walker and Terra and the “senseless acts of cruelty” that were carried out.

“They will be truly missed in this parish. Very peaceful people, very peaceful men, loving, kind and charitable,” Harmon said.

“They are truly concerned about the sanctity of souls, and saving souls,” she added. “It’s hard to imagine, but that’s unfortunately the society we’re living in, a godless society. It’s lawless.”

Phoenix Mayor Greg Stanton said the city was shocked and saddened as police pleaded for the public’s help in identifying the suspects.

“The tragedy that occurred last night at the Mother of Mercy Mission church strikes at our core because every American should feel safe in a house of worship â€” and that basic value was violated last night in an unspeakable way,” Stanton said.

Terra and Walker, 28, served as pastor and assistant pastor, respectively, and they both lived in the church, which is located along a gritty stretch of downtown Phoenix. The Rev. Fred Adamson, vicar general of the Phoenix Archdiocese, said both men believed the church “was a safe place to live.”

They both belonged to the Priestly Fraternity of St. Peter, and one of its hallmarks is leading Mass in Latin for worshippers.

Police found an abandoned car they were seeking in connection with the attack about four blocks from the church, Sgt. Steve Martos said.

Rorate Caeli, an online blog widely read in Vatican circles, said Walker was born in upstate New York near Poughkeepsie. He was the middle child among a family of 11 children. He was ordained in May 2012.